1. Field of the Invention
The present invention generally relates to an temperature control method and apparatus of a heating/ventilation/air-conditioning (HVAC) system for efficiently saving energy in a building management system.
2. Description of the Related Art
The Internet, which is a human centered connectivity network where humans generate and consume information, is now evolving to the Internet of Things (IoT) where distributed entities, such as things, exchange and process information without human intervention. The Internet of Everything (IoE), which is a combination of the IoT technology and the Big Data processing technology through connection with a cloud server, has emerged. As technology elements, such as “sensing technology”, “wired/wireless communication and network infrastructure”, “service interface technology”, and “security technology” have been demanded for IoT implementation, a sensor network, a Machine-to-Machine (M2M) communication, Machine Type Communication (MTC), and so forth, have been recently researched.
Such an IoT environment may provide intelligent Internet technology services that create a new value to human's life by collecting and analyzing data generated among connected things. IoT may be applied to a variety of fields including smart home, smart building, smart city, smart car or connected cars, smart grid, health care, smart appliances and advanced medical services through convergence and combination between existing Information Technology (IT) and various industrial applications.
In general, buildings, such as hotels or office buildings, have an energy control system for effectively controlling energy. Such an energy control system performs occupancy detection using a door lock, a motion sensor, or the like, and when non-occupancy of a user is detected, it performs setback control based on the detection result. The setback control is a control method of temporarily changing a set temperature of a room in order to save energy during a time period, such as at night, when no user is in the room. The setback control may be initiated immediately when non-occupancy of a user is detected or when non-occupancy of the user is maintained for a predetermined time after being detected. In the former case, if the user goes out for a while and then comes back again, more energy may be consumed than the case in which the user stays in a room. That is because more energy consumption is required than usual for instantaneous temperature control when the user comes back again. In the latter case, energy may be additionally consumed until the setback control is initiated after the detection of the non-occupancy state.
In the case of static setback control using a constant value, when a user comes back, a lot of time is required in returning to a normal temperature such that the user may feel uncomfortable for the corresponding period of time. Therefore, even when the user stays out for a long time, it is not appropriate to turn the power off for energy saving. Further, in view of the characteristics of devices, the temperature which each device can change within a predetermined time may be extracted, and dynamic setback control may be performed based on the extracted temperature. However, such a method does not consider the time of the occupancy of a user. Therefore, energy efficiency is not good, and the user may not be serviced comfortably at the time of his/her occupancy using the static setback control. Furthermore, a method of detecting occupancy using a motion sensor or a door lock is also ineffective in handling various situations, such as a blind spot of the motion sensor, or when several users are in the area.
Moreover, in the case of hotels, demands of the user and energy saving differ from each other according to types of the hotels. Accordingly, a method for satisfying the above conditions in an HVAC system is required.